最终结果是我试图在我的操作系统10.7.3上安装Ruby on Rails，但遇到各种问题。
另外，我从App Store新安装了XCode 4.3。
当我启动终端时，输入：
sudo gem install rails
并写出：
Building native extensions. This could take a while...
ERROR: Error installing rails:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ruby.h
Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/json-1.6.5 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/json-1.6.5/ext/json/ext/parser/gem_make.out
在我发现的所有修复程序中都说安装XCode，我已经运行并且运行得很好。但是，我确实卸载了以前版本的XCode来安装最新版本，所以我想知道那里是否有任何关系。
编辑1： 我遵循了Jasdeep的建议并安装了RVM。但是一旦我跑了：
sudo rvm install 1.9.3
我得到以下内容：
Fetching yaml-0.1.4.tar.gz to /Users/xxx/.rvm/archives
Extracting yaml-0.1.4.tar.gz to /Users/xxx/.rvm/src
Configuring yaml in /Users/xxx/.rvm/src/yaml-0.1.4.
Error running ' ./configure --prefix="/Users/xxx/.rvm/usr" ', please read /Users/xxx/.rvm/log/ruby-1.9.3-p0/yaml/configure.log
Compiling yaml in /Users/xxx/.rvm/src/yaml-0.1.4.
Error running 'make ', please read /Users/xxx/.rvm/log/ruby-1.9.3-p0/yaml/make.log
Database file /Users/xxx/.rvm/config/packages does not exist.
gcc-4.2: error trying to exec '/usr/bin/i686-apple-darwin11-gcc-4.2.1': execvp: No such file or directory
Installing Ruby from source to: /Users/xxx/.rvm/rubies/ruby-1.9.3-p0, this may take a while depending on your cpu(s)...
ruby-1.9.3-p0 - #fetching
ruby-1.9.3-p0 - #downloading ruby-1.9.3-p0, this may take a while depending on your connection...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 9330k 100 9330k 0 0 645k 0 0:00:14 0:00:14 --:--:-- 1260k
ruby-1.9.3-p0 - #extracting ruby-1.9.3-p0 to /Users/xxx/.rvm/src/ruby-1.9.3-p0
ruby-1.9.3-p0 - #extracted to /Users/xxx/.rvm/src/ruby-1.9.3-p0
ruby-1.9.3-p0 - #configuring
Error running ' ./configure --prefix=/Users/xxx/.rvm/rubies/ruby-1.9.3-p0 --enable-shared --disable-install-doc --with-libyaml --with-opt-dir=/Users/xxx/.rvm/usr ', please read /Users/xxx/.rvm/log/ruby-1.9.3-p0/configure.log
There has been an error while running configure. Halting the installation.
然后我查看了日志文件中的内容，..ruby-1.9.3-p0 / yaml / configure.log：
[2012-03-03 22:49:50] ./configure --prefix="/Users/xxx/.rvm/usr"
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... config/install-sh -c -d
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... no
checking for gcc... no
checking for cc... no
checking for cl.exe... no
configure: error: in `/Users/xxx/.rvm/src/yaml-0.1.4':
configure: error: no acceptable C compiler found in $PATH
See `config.log' for more details
现在看来错误是：
no acceptable C compiler found in $PATH
编辑2：
我遵循了matt的说明，并且一旦安装了命令行工具就可以进一步（因为我现在有Xcode 4.3）。但是，我仍然收到错误：
Fetching yaml-0.1.4.tar.gz to /Users/xxx/.rvm/archives
Extracting yaml-0.1.4.tar.gz to /Users/xxx/.rvm/src
Configuring yaml in /Users/xxx/.rvm/src/yaml-0.1.4.
Compiling yaml in /Users/xxx/.rvm/src/yaml-0.1.4.
Installing yaml to /Users/xxx/.rvm/usr
gcc-4.2: error trying to exec '/usr/bin/i686-apple-darwin11-gcc-4.2.1': execvp: No such file or directory
Installing Ruby from source to: /Users/xxx/.rvm/rubies/ruby-1.9.3-p0, this may take a while depending on your cpu(s)...
ruby-1.9.3-p0 - #fetching
ruby-1.9.3-p0 - #extracted to /Users/xxx/.rvm/src/ruby-1.9.3-p0 (already extracted)
ruby-1.9.3-p0 - #configuring
Error running ' ./configure --prefix=/Users/xxx/.rvm/rubies/ruby-1.9.3-p0 --enable-shared --disable-install-doc --with-libyaml --with-opt-dir=/Users/xxx/.rvm/usr ', please read /Users/xxx/.rvm/log/ruby-1.9.3-p0/configure.log
There has been an error while running configure. Halting the installation.
以下是configure.log（对不起，这篇文章已经过了很长时间，但希望它也可以帮助其他人）：
[2012-03-04 09:29:35] ./configure --prefix="/Users/xxx/.rvm/usr"
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... config/install-sh -c -d
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking for style of include used by make... GNU
checking dependency style of gcc... gcc3
checking how to run the C preprocessor... gcc -E
checking whether ln -s works... yes
checking whether make sets $(MAKE)... (cached) yes
checking build system type... x86_64-apple-darwin11.3.0
checking host system type... x86_64-apple-darwin11.3.0
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for fgrep... /usr/bin/grep -F
checking for ld used by gcc... /usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld
checking if the linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) is GNU ld... no
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm
checking the name lister (/usr/bin/nm) interface... BSD nm
checking the maximum length of command line arguments... 196608
checking whether the shell understands some XSI constructs... yes
checking whether the shell understands "+="... yes
checking for /usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld option to reload object files... -r
checking for objdump... no
checking how to recognize dependent libraries... pass_all
checking for ar... ar
checking for strip... strip
checking for ranlib... ranlib
checking command to parse /usr/bin/nm output from gcc object... ok
checking for dsymutil... dsymutil
checking for nmedit... nmedit
checking for lipo... lipo
checking for otool... otool
checking for otool64... no
checking for -single_module linker flag... yes
checking for -exported_symbols_list linker flag... yes
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if gcc supports -fno-rtti -fno-exceptions... no
checking for gcc option to produce PIC... -fno-common -DPIC
checking if gcc PIC flag -fno-common -DPIC works... yes
checking if gcc static flag -static works... no
checking if gcc supports -c -o file.o... yes
checking if gcc supports -c -o file.o... (cached) yes
checking whether the gcc linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) supports shared libraries... yes
checking dynamic linker characteristics... darwin11.3.0 dyld
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking for doxygen... false
checking for ANSI C header files... (cached) yes
checking for stdlib.h... (cached) yes
checking for an ANSI C-conforming const... yes
checking for size_t... yes
configure: creating ./config.status
config.status: creating yaml-0.1.pc
config.status: creating include/Makefile
config.status: creating src/Makefile
config.status: creating Makefile
config.status: creating tests/Makefile
config.status: creating win32/Makefile
config.status: creating config.h
config.status: config.h is unchanged
config.status: executing depfiles commands
config.status: executing libtool commands
答案 0 :(得分：45)
问题在于Lion Xcode 4.3默认情况下不安装（甚至包括）gcc等命令行工具 - 这些都是这里需要的。在Xcode的首选项的“下载”窗格中，在“组件”下，请求命令行工具。 （参见自述文件：https://developer.apple.com/library/content/documentation/DeveloperTools/Conceptual/WhatsNewXcode/Chapters/xcode_4_0.html#//apple_ref/doc/uid/TP40016147-SW35）
实际上我相信你根本不需要安装Xcode，因为实际上命令行工具现在可以单独下载和安装。
答案 1 :(得分：5)
我已安装了命令行工具（xCode也是如此）......但仍有此（初始）错误。
问题是xCode和命令行工具不再安装gcc编译器。我不知道他们什么时候停止运输它，但我跑山狮，它不在这里。 所以最终解决了我的问题的是从头开始安装gcc（https://github.com/kennethreitz/osx-gcc-installer）。
继续微笑：）
答案 2 :(得分：4)
如果有人对Ubuntu Linux有同样的问题，解决方案是：
sudo apt-get install build-essential
sudo apt-get install libsqlite3-dev